Article 6, Clause 3
James Madison to Edmund Randolph10 Apr. 1788Papers 11:19
As to the religious test, I should conceive that it can imply at most nothing more than that without that exception, a power would have been given to impose an oath involving a religious test as a qualification for office. The constitution of necessary offices being given to the Congress, the proper qualifications seem to be evidently involved. I think too there are several other satisfactory points of view in which the exception might be placed.
The Founders' Constitution
Volume 4, Article 6, Clause 3, Document 22
The University of Chicago Press
The Papers of James Madison. Edited by William T. Hutchinson et al. Chicago and London: University of Chicago Press, 1962--77 (vols. 1--10); Charlottesville: University Press of Virginia, 1977--(vols. 11--).
Easy to print version.